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Equus Innova 3320 digital multimeter

Equus 3320 auto-ranging digital multimeter

The Equus 3320 digital multimeter is a general-purpose instrument designed for use in general electronics, automotive electronic systems and home electrical applications. The auto-ranging scale eliminates the need to set the correct range when making electronic measurements. It has a large LCD display and a handy color-coded LED display for battery quick check. The protective rubber corner guards for drop protection.

General specifications and features

  • 3 ½ digit large LCD display
  • 3 LEDs: green, yellow and red
  • Auto Range for ACV, DCV, Ohms, AC mA and DC mA)
  • Pollution Degree: 2
  • Measuring circuit category: II
  • Automatic negative (-) polarity indication
  • Automatic zero adjustment
  • Low battery indicator - displays battery symbol on LCD
  • Over-range indicator (except on the 10A range) - displays "OL" on LCD
  • Automatic power off after 15 idle minutes
  • Operating environment
    - Temperature: 32°-104°F (0°C to 40°C)
    - Humidity: less than 80% relative humidity (non-condensing)
    - Altitude: up to 6562 ft (2000 meters)
  • Storage environment
    - Temperature: 4° to 140°F (-20° to 60°C)
    - Humidity: less than 90% relative humidity (non-condensing)
  • Power Supply: Two 1.5V AA batteries
  • Fuse: 315mA/250V 5X20 mm fuse
  • Dimensions: Height: 139x89x32mm
  • Weight (including batteries): approximately 180g

Electrical specifications

DC volts

Input Resistance: 10MΩ
Overload Protection: 600V DC or AC 600V RMS.

Range Resolution Accuracy
200.0mV 0.1mV±(0.8% of rdg + 5 digits)
2000V 1mV±(0.8% of rdg + 5 digits)
20.00V 10mV±(0.8% of rdg + 5 digits)
200.0V 100mV±(0.8% of rdg + 5 digits)
600V 1V±(0.8% of rdg + 5 digits)

AC Volts

Input Resistance: 10MΩ
Overload Protection: 600V DC or AC 600V RMS.
Frequency Response: 50Hz - 400Hz

Range Resolution Accuracy
2.000V 1mV±(1.2% of rdg + 5 digits)
20.00V 10mV±(1.2% of rdg + 5 digits)
200.0V 100mV±(1.2% of rdg + 5 digits)
600V 1V±(1.2% of rdg + 5 digits)

Resistance (Ohms)

Overload Protection: 250V DC or AC RMS.

Range Resolution Accuracy
200.0Ω 0.1Ω±(1.0% of rdg + 5 digits)
2000kΩ±(1.0% of rdg + 5 digits)
20.00kΩ 10Ω±(1.0% of rdg + 5 digits)
200.0kΩ 100Ω±(1.0% of rdg + 5 digits)
2.000MΩ 1kΩ±(1.0% of rdg + 5 digits)
20.00MΩ 10kΩ±(2.0% of rdg + 5 digits)

DC Amps

Input Voltage Drop: less than 0.2V

Overload Protection: 315mA/250V fuse for the 2 lower ranges. The 2A and 10A range is unfused - a maximum testing time of 15s is recommended! For the 10A range a waiting period of at least 15 minutes is necessary between every 15 second testing period!

Range Resolution Accuracy
20.00mA 10µA±(1.0% of rdg + 5 digits)
200.0mA 100µA±(1.0% of rdg + 5 digits)
2.000A 1mA±(2.0% of rdg + 5 digits)
10.00A 10mA±(2.0% of rdg + 5 digits)

AC Amps

Input Voltage Drop: less than 0.2V
Overload Protection: 315mA/250V fuse.

Range Resolution Accuracy
20.00mA 10µA ±(1.5% of rdg + 5 digits)
200.0mA 100µA±(1.5% of rdg + 5 digits)

Diode test

Range: 2V
Resolution: 1mV
Test Current: 1±0.6mA
Test Voltage: ~1.5V
Overload Protection: 250V DC or AC RMS.

Continuity test

Range: 200Ω
Resolution: 0.1Ω
The buzzer will sound for a measurement of 120Ω or less.
Overload Protection: 250V DC or AC RMS.

BATTERY TEST (LEDs)

Accuracy: ±(5% of rdg + 5 digits)
Note: When the voltage of the battery being tested is lower than 10% of its rated voltage, the red LED will not light.

1.5V
Resolution: 0.001V
Load current: ~10mA
Green LED: for 1.30V ±0.075V and up.
Yellow LED: for 0.94V ±0.075V to 1.29V ±0.075V
Red LED: for 0.15V±0.075V to 0.93V±0.075V.

6V
Resolution: 0.01V
Load current: ~100mA
Green LED: 5.22V ±0.3V and up
Yellow LED: 3.76V ±0.3V to 5.21V±0.3V
Red LED: 0.6V±0.3V to 3.75V±0.3V.

9V
Resolution: 0.01V
Load current: ~10mA
Green LED: 7.83V ±0.45V and up
Yellow LED: 5.64V ±0.45V to 7.82V±0.45V
Red LED: 0.9V±0.45V to 5.63V±0.45V.

12V
Resolution: 0.01V
Load current: ~200mA
Green LED: 10.44V ±0.6V and up
Yellow LED: 7.52V ±0.6V to 10.43V±0.6V
Red LED: 1.2V±0.6V to 7.51V±0.6V.

Operating instructions

Read your user manual and make sure you understand the dangers involved when working with devices under high voltage. Before every use, inspect the test leads for damage - check for cracked insulation, broken or damaged probes, loose or bent probe pins. Inspect the multimeter for damage to the case. Do not use the instrument, if cracked, distorted, excessively dirty or any abnormal condition exists.

Set the Function/Range switch to the proper range before taking measurements. If the range/function must be switched during a test, remove the test leads from the circuit being measured before switching settings.

To avoid possible electric shock, instrument or equipment damage when taking voltage or current measurements, do not exceed the maximum value of the selected range.

If the meter is used near high noise Radio Frequency (RF) generating equipment like spark plug wires, ignition coils or an alternator, the display may become unstable or indicate large errors. If you obtain erratic readings during use, isolate the instrument as far away as possible from these components.

Jack inputs

The jack on the left side is the DC 10A input for the red test lead probe connection when measuring high DC currents up to 10 amps. This input is unfused, never use it to measure currents above 10A! The COM Input Jack is placed on the middle. Use this for the black lead only. On the right of the instrument is placed the jack for Volts, mA, OHMS, BAT, DIODE and CONTINUITY for the red probe.

AC/DC Voltage measurement

To avoid possible electric shock, instrument or equipment damage, do not attempt to measure voltages above 600V AC/DC. This is the maximum voltage that this instrument is designed to measure. The "COM" terminal potential should not exceed 300V AC/DC measured to ground.

1. Plug the black test lead into "COM" jack of the multimeter then plug the red test lead into the "V" jack.

2. Set the multimeter's Function/Range Selector switch to the appropriate ACV or DCV position as desired .

3. Place the red test lead onto the positive (+) side of the item being tested and the black test lead onto the negative (-) (across the source/load) side of the item. Be careful not to touch any energized conductors with any part of your body.

4. Read the results on the display.

Resistance measurement (Ohms)

Resistance measurements must be made on deenergized circuits only. Impressing a voltage across the meter's terminals while set to any resistance range may result in electric shock, damage to the instrument or the equipment under test. Make sure the equipment is completely de-energized before taking any resistance measurements!

To obtain accurate readings, disconnect at least one side of the resistor under test from the circuit or circuit board before measuring resistance. Tip: confirm the measurements for color coded resistors using a color code calculator.

1. Plug the red test lead into the "Ω" jack of the multimeter; plug the black test lead into the "COM" jack.

2. Set the multimeter's Function/Range selector switch to the "Ω" range function.

3. Place the red test lead onto one side of the item being tested and the black test lead onto the other side of the item. Note, that polarity does not matter when checking resistances.

4. Read the results on the display.

Diode test

To avoid electrical shock or damage to the multimeter, ensure the power is removed from the circuit before any diode testing procedures are conducted. Test diodes on deenergized circuits only, never on live circuits.

Disconnect at least one side of the the diode from the circuit before testing. A good diode will show a low voltage drop across its junction - 0.5-0.8 volts for a silicon diode or about 0.3V for a germanium diode - when the leads are connected in one polarity and a very high resistance when the leads are reversed.

1. Plug the red test lead into the diode jack of the multimeter; plug the black test lead into the "COM" jack.

2. Set the meter's Function/Range Selector switch to the diode test position.

3. Place the red test lead onto one side of the diode being tested and the black test lead onto the other side.

4. Read the results on the display.

5. Reverse the test leads and again read the results on the display. Compare the two readings - one reading should indicate a voltage drop - the other reading should indicate an overrange (OL) condition.

Continuity test

The buzzer will sound only if the continuity of the item under test measures less than 120 ohms. Make sure to disconnect the power source from the equipment under test before testing it for continuity!

1. Plug the red test lead into the buzzer jack of the multimeter and plug the black test lead into the "COM" jack.

2. Set the multimeter's Function/Range selector switch to the buzzer position.

3. Place the red test lead to one end of the wire or component being tested for continuity and the black test lead to the opposite end.

4. Listen to the sound of the beeper and confirm the results by reading the display.

DC/AC Current measurement (Amps)

Note, that the DC 10A range is not fused. To avoid current hazard or damage to the tester, do not try to take measurements on circuits that have more than 10 ampers. Do not take more than 10 seconds to take the reading. A waiting period of at least 15 minutes is necessary between every 15 second testing period!

To measure current on a particular circuit, you must open up the circuit and connect the test leads in series with the circuit. After the test is completed, shut the power off to the circuit before removing the test leads and before reconnecting any disconnected wires or devices.

1. Plug the red test lead into the "mA" or the "DC 10A" jack of the multimeter, as applicable. Plug the black test lead to the "COM" jack.

2. Set the multimeter's Function/Range selector switch to the appropriate Amps range position as desired. To measure from 0 to 200mA, set the selector switch to the "DCmA" or "ACmA" position, as applicable. To measure from 200mA to 10 Amps DC, set the selector switch to the "DC 10A" position.

3. Disconnect the battery, or shut off the power to the circuit being tested.

4. Disconnect one end of the wire or device, from the circuit where the current will be measured.

5. Place the red test lead on the disconnected wire and place the black test lead at the location from which the wire was disconnected (series connection).

6. Reconnect the battery, or apply power to the circuit being tested.

7. Read the results on the display.

Battery test

Battery life is directly proportional to the current draw/load of the device that the battery is powering. The 3 LEDs on the meter represent battery state-of-charge averages for the most commonly used devices. If the battery is below 10% of its rated voltage, the red LED will not light.

1. Plug the red test lead into the "BAT" jack of the multimeter, then plug the black test lead into the "COM" jack.

2. Determine the voltage rating of the battery to be tested.

3. Set the multimeter's Function/Range selector switch to the desired "Battery Test" range.

4. Place the red test lead on the positive pin of the battery under test. Place the black lead on the negative end.

5. Read the results using the display and the LEDs as follows:
- Green indicates a fully charged, good battery
- Yellow will light for a low (questionable) battery
- Red means the battery is discharged (bad).